Field of the Invention
The present invention concerns a method for making a valve for regulating a fluid, the valve including a valve housing with a central part and with one, two or more connection ends, the connection ends extending away from the central part, wherein internally of the central part there is arranged a valve body, for example with a through-going opening, the valve body arranged in a valve seat and connected to a valve spindle, the valve spindle arranged in a spindle guide stub on the valve housing.
The invention furthermore concerns a valve for regulating a fluid, the valve including a valve housing with a central part and with one, two or more connection ends, the connection ends extending away from the central part, wherein internally of the central part there is arranged a valve body, for example with a through-going opening, the valve body arranged in a valve seat and connected to a valve spindle, the valve spindle arranged in a spindle guide stub on the valve housing.
Description of Related Art
It is commonly known to make valves, e.g., ball valves, and thereby valve housings of several parts and then assemble these parts around a valve seat and a valve body. Such valves are typically made of brass or other cupper-based alloy and are typically assembled by corresponding screw threads in respective parts, or alternatively by means of bolts. The spindle guide stub will typically be mounted with a threaded joint or by a welding on the valve housing itself.
When speaking of a ball valve, the valve body is, as indicated by the name, spherical and with an outer size which is greater than the connecting openings in the valve housing. Such a valve therefore has a valve housing with an internal geometry in which valve seat and valve body are disposed. The valve housing is typically joined in the vicinity of the valve body as the latter requires the largest internal dimension. Such valves are typically made of cast workpieces which are formed and shaped by machining into the desired geometry. This shaping process is, however, rather cost-intensive for several reasons. The individual workpieces are to be cast and then handled and machined one by one in a suitable metal cutting unit. Since the workpieces are individually machined, the process is time-consuming, irrespective of the application of modern and rapid processes.
In addition to the handling and machining of the cast workpieces prior to assembling around a valve seat and a valve body, the cost of the material also plays a significant role. Brass or other suitable alloys are expensive and imply an appreciably greater cost than, e.g., common weldable carbon steel.
German Patent Application DE 3503030 A1 discloses a valve that comprises a valve housing with a central part and with two or more connection ends, the connection ends extending away from the central part, and where internally of the central part there is arranged a valve body arranged in a valve seat and connected to a valve spindle. The valve spindle is arranged in a spindle guide stub on the valve housing, which is made of a tubular workpiece and includes a spindle guide stub, the spindle guide stub being welded on the tubular workpiece in a traditional way.
There is thus an expressed desire for making valves for heating and cooling systems, for potable water and for other purposes in steel, e.g., carbon steel or stainless steel which is cheaper and which can be worked with modern production equipment directly from a plate piece or a tube piece faster and cheaper than possible when casting and machining workpieces of brass.
At the same time, it is greatly desired to perform as few welding processes as possible on a valve as such processes cause the work pieces to be set up at least one more time and as a welding process is to be performed, which of course raise the cost of the product.
Finally, crevice corrosion can arise in cavities between two surfaces in a joint, e.g., in threaded joints, which may cause a substantially shortened service life of the valves so that they have to be removed from the system due to the crevice corrosion. Therefore, it is also greatly desired to avoid such joints between the valve parts where there is a risk that crevice corrosion will occur.